The present invention generally relates to a system and method for the generation and delivery of high pressure gas-supersaturated fluids. More specifically, the present invention relates to a system and method for generating a gas-supersaturated fluid and delivering the fluid at high pressures without bubble formation.
Prior art infusion devices have been developed for drug delivery, angiographic dye injection and precision fluid infusion. In general, such infusion devices only support small delivery volumes (approximately 60 cc) at low (for example, less than 20 psi) to medium (for example, up to 1000 psi) delivery pressures.
A system and method capable of delivering-a large volume of fluid at an accurate delivery rate may be desirable, for example, for enriching blood with an oxygen-supersaturated solution to provide regional or systemic support to a patient. Another application of oxygen supersaturated fluid would be delivery downstream of a balloon angioplasty site, such as by perfusion guidewire, to reduce or prevent localized ischemia. For delivery and infusion of gas-supersaturated fluids, such as an oxygen supersaturated solution, a high delivery pressure (for example, 4,000 psi) may be desirable to prevent bubble nucleation or formation. An example of a system for delivering gas supersaturated fluids without bubble formation is disclosed in U.S. Pat. No. 5,599,296. When fluid is delivered at high pressures, it is also desirable to provide a safety mechanism for terminating fluid delivery when the delivery pressure exceeds a predetermined limit.
In order to deliver the fluid at a desired volume delivery rate and/or to deliver a desired total volume of the fluid, it is also desirable to provide accurate control of the delivery rate and thus accurate control of the total fluid volume delivered.
In spite of recent advances in the art, for example the above-mentioned U.S. Pat. No. 5,599,296, there remains a need in the art for a fluid delivery system and method for generating and accurately delivering a large volume of gas-supersaturated fluid. There remains a further need in the art for a system capable of generation and delivery of gas-supersaturated fluid at high delivery pressures in order to prevent or minimize bubble nucleation and formation upon infusion into a patient. There remains yet a further need in the art for a fluid delivery system and method for providing a safety mechanism to protect patients and operators by interalia, terminating the fluid delivery if the delivery pressure exceeds a predetermined limit. There remains yet a further need in the art for a fluid delivery system and method for accurate control of the delivery rate and pressure and thus accurate control of the total fluid volume delivered.
Preferred embodiments of the present invention meet the foregoing needs by providing a system and method for generating a large volume of gas-supersaturated fluid and delivering the fluid to a fluid delivery device at specified fluid delivery rates and at high delivery pressures to prevent bubble nucleation.
The fluid delivery system of the present invention comprises a system housing for containing a removable fluid housing assembly and a drive mechanism assembly. The removable fluid housing assembly comprises a cylindrical fluid housing and a piston which travels along the inner surface of the fluid housing.
The fluid housing assembly is first removed from the system housing and filled with a fluid. The fluid in the fluid housing assembly is supersaturated by introducing a gas at or slightly above the desired gas partial pressure of the fluid. The fluid housing assembly is then returned to the system housing and the drive mechanism assembly advances the piston to increase the hydrostatic pressure of the fluid within the fluid housing until the desired delivery pressure is obtained.
Use of the fluid housing for both generating and delivering the gas-supersaturated fluid simplifies the system configuration by eliminating additional components and also simplifies the method for generating and delivering the gas-supersaturated fluid by eliminating the step of transporting the fluid from one fluid housing to another. Generating and delivering the gas-supersaturated fluid in a single fluid housing also greatly minimizes the issues of corrosion of the fluid housing, contamination of the fluid and bubble nucleation in the fluid.
After the hydrostatic pressure of the fluid within the fluid housing reaches the desired delivery pressure, the gas-supersaturated fluid is delivered through a fluid output tubing for delivery of the fluid to a desired delivery site. For fluid delivery to a patient, for example, a hollow perfusion guide wire or other appropriate delivery device is connected to one end of the fluid output tubing. The fluid delivery rate is controlled and can range from 1 ml/hr to greater than 3,000 ml/hr.
The system of the present invention provides a compact system for generation and delivery of gas-supersaturated solutions in a configuration and size very similar to conventional infusion pumps.